Floor panels, such as laminate floor panels or wood fibre floor (WFF) panels, are usually provided with a balancing layer on a rear side of the panel. The balancing layer may also be called a backing layer or counteracting layer. On the opposite side of the core, a decorative surface layer is arranged. The decorative layer may comprise a resin impregnated décor paper and a resin impregnated overlay paper. The decorative layer may also be a surface layer formed from a mix comprising wood fibres and a thermosetting binder as described in WO2009/065769. Such floor panels are marketed under the trademark NADURA®.
When the thermosetting binder in the decorative surface layer, for example, melamine formaldehyde resin, is cured, shrinking of the melamine formaldehyde resin leads to tension in the decorative surface layer. The internal stress formed in the decorative surface layer may cause warping of the panel. The tension at the front side of the panel should be compensated by a counteractive tension at the rear side of the panel. Therefore, a balancing layer is arranged on a rear side of the core opposite the decorative surface layer. The balancing layer is adapted to counteract and balance tension formed during curing of the decorative surface layer. The balancing layer may be a resin impregnated paper or a formed of a mix comprising wood fibres and a thermosetting binder of the type described in WO2012/141647.
An article by Le Fur et al. (“Recycling melamine-impregnated paper waste as board adhesive”, Holz als Roh- and Werkstoff, Vol. 62, 2004, pp. 419-423, ISSN 0018-3768) discloses use of melamine impregnated paper offcuts and waste. In one approach, the melamine impregnated waste paper is used as a binder for forming a particleboard. The melamine waste paper was applied to wood particles, and no other binder was added in order to form the particleboard. In a second approach, melamine impregnated paper is used as a melamine substitute during the formulation of and preparation of liquid melamine-urea-formaldehyde (MUF) resins. The resin is centrifuged to separate the resin from the cellulose fibre originating from the melamine waste paper. The resin including the melamine part of the waste material was applied to wood particles for forming a particleboard.
It is a general desire of floor producers to decrease the cost for producing the floor panels. The balancing layer is one area where improvements relating to cost reduction is desirable.